To strengthen the muscles and ligaments of the lower body, it is known in physical education to perform exercises directed to hopping, running, jumping, lifting weights, etc. on the balls of the person's feet. In so doing, a person will strengthen many of the major muscle groups of the feet, legs and lower torso. The efficacy of these exercises is directly related to the amount of weight borne on the forward part of the foot of the user, and also directly related to the number of repetitions of each exercise so performed.
U.S. Pat. No. 3,739,500 to Cox describes a shoe, and the use thereof, with a platform integrally attached to the front of the shoe. In Cox, an exercise shoe having attached thereto a flexible pillar sole member for causing the wearer to stand, walk and run on the balls of the feet, thereby maximizing the effect and potential benefit of any repetitions performed. The benefits of training on elevated front foot shoes are well described in Cox. Many athletes prefer to obtain such benefits wearing their normal training shoes.
Cox alludes to the possibility of attaching his extension separately to conventional athletic shoes: " . . . the extension with its ground contacting sole may be separately manufactured and suitably attached to conventional athletic shoes." (column 2, lines 52-54) The challenge heretofore has been to attach platforms removably to the wearer's normal training shoes, such that they remain securely attached during rigorous running and jumping, yet are removable after use. The absence, so far, of a commercially successful separate shoe extension stems from the fact that a satisfactory design has proved elusive. If the platforms were to be attached securely enough, they had to be attached to the shoe with some degree of permanence, such as being glued onto the bottoms, or being bolted through holes drilled into the sole. If the platforms were to be attached removably enough, they were somehow strapped onto or tied to the shoe making them prone to shifting or slipping off during the course of vigorous exercise. The present invention offers a novel solution providing the functions of both secure attachment and easy removability.
The exercise shoe of Cox has several limitations: (1) it is an expensive piece of equipment, consisting of an entire shoe; (2) it is a size specific piece of equipment, a pair only usable by individuals having the same shoe size; (3) it is a complete shoe, the user of which cannot use the athletic shoe which he uses in competition while using the exercise shoe (this is to many athletes a significant problem in that to maximize their performance they prefer to train in the same shoes in which they compete); (4) it is a shoe which prevents training in one's bare feet (many athletes, particularly sprinters and distance runners prefer to exercise and compete in their bare feet); and (5) it is a bulky piece of equipment, requiring significant space allotment.